The identification of LSCs in acute lymphocytic leukemia (ALL) has proved challenging, as transplantation studies in immunocompromised mice have yielded conflicting results. The distinction between Philadelphia chromosome-positive (Ph+) ALL and lymphoid blast crisis (LBC) chronic myeloid leukemia (CML) is also controversial. Leukemia appears to retain some semblance of the normal hematopoietic hierarchical structure: i.e., rare leukemic stem cells (LSCs) with self-renewal capacity give rise to partially differentiated progeny that comprise the bulk of the leukemia but possess only limited proliferative potential. Existing therapies, although highly active against the leukemic bulk, are often ineffective against the hardier LSCs responsible for relapse. Therefore, a need exists for identifying LSCs in patients with a hematopoietic disorder that is not acute myelogenous leukemia (AML), such as ALL so that the patients can be identified as having a high or low risk for relapse and appropriate treatment can be delivered.
The present invention overcomes previous shortcomings by providing methods and compositions for identifying LSCs in patients with a hematopoietic disorder that is not AML, such as ALL.